Advent of Clojure solutions

forkme.clj

(ns adventofcode2015.core)

(defn step [[row column value]]
  (let [new-value (mod (* value 252533) 33554393)
        max-depth (dec (+ row column))
        new-row (if (= column max-depth) (inc max-depth) (dec row))
        new-column (if (= column max-depth) 1 (inc column))]
    [new-row new-column new-value]))


(def initial [1 1 20151125])

(->> (iterate step initial)
     (filter (fn [[row column _ _]]
               (and  (= row 3010) (= column 3019))) )
     (first))

(comment (defn index [row column]
           (- (reduce + (range (+ row column))) (dec row))))